In a variety of wellbore drilling operations, wired drill pipe is used to carry signals along the wellbore. Each wired drill pipe comprises conductive end connections that enable the connection of a series of wired drill pipes to form a wired drill string. The wired drill pipe is deployed by a drilling system having a rig, such as a land-based rig or an off-shore rig. The drill string is suspended in the wellbore by the rig; and a drill bit at the lower end of the drill string is used for drilling the wellbore.
Electrical connections between wired drill pipes are formed via a variety of mechanisms and in various configurations. For example, electrical connections between drill pipes have been created with the aid of several types of springs. However, such spring connections can have problems with long-term reliability, mating alignment, and other issues.
In other applications, inductive couplers have been used to enable transfer of signals along wired drill strings, and those connections are useful in many environments. However, inductors effectively amplify the connection resistance by the square of the number of turns in the inductor. For example, with 100 turn inductors, 10 milliohms of connection resistance effectively becomes 10 ohms of connection resistance when reflected through the inductors. As a result, very low connection resistance is desired, but low connection resistance is nearly impossible when forming wired drill pipe connections in the field. Debris between connectors, glazing, corrosion, and other effects can also increase the connection resistance.